The magnetic head is by far the most expensive component of magnetic tape drive computer equipment. The head costs two to three times more than any of the other components. In spite of the fact that the cost of almost all of the other components of a computer have been dramatically reduced during the last ten to fifteen years, the construction and the cost of the magnetic heads has remained the same. These are very critical components of all magnetic tape drives, and the tolerances for stability and positioning accuracy of these heads must be kept to within forty to fifty millionths of an inch.
Some time ago, a sprayed-on ceramic wear coating was developed for tape-engaging heads for computer memory systems. In 1972, I prepared an article which was published in Electronics Magazine for June 19, 1972 which described this spraying process in conjunction with the development of the ceramic wear coating material. This sprayed-on wear coating is accomplished with high temperature (up to 30,000.degree. F.) spraying techniques. The spraying operation deposits a coating of a material which is fed into a jet stream of extremely hot, high-speed, inert gases produced within a spray gun such as is manufactured by Metco, Inc., Westbury, Long Island, N.Y. (type 7M plasma gun).
At the present time, brass is the most common material used for the base or substrate. Brass is not only extremely heavy, but is also relatively expensive when compared with molded plastic material. Due to the extremely high temperatures of the sprayed-on, wear-resistant material, plastic has not been used as a substrate and was not believed to be a feasible material for this purpose; however, I have discovered that by carefully controlling the temperature rise of the prepared substrate body during the depositing of the layer of stabilizing, wear-resistant material on the tape-engaging wear surface of the plastic body, an inexpensive, light-weight magnetic head can be successfully produced. A magnetic head embodying this invention can be produced for only forty to fifty percent of the cost of producing the present heads usinq a brass substrate. This is a reduction of between fifty and sixty percent in the selling price of this component.